This invention finds application in treatment and upgrading of heavy crude oil and bitumen. These materials are commonly very viscous and dense liquid scontaining various concentrations of sulfur. Pipeline companies penalize heavy crude oil producers for the quality of crude oil produced. These penalties can result in price deductions from undesirable oil properties related to density, sulfur content, and viscosity.
A common practice by heavy oil producers is to add condensate (low boiling liquid hydrocarbon) to the produced crude oil to meet viscosity specifications for pipeline shipment. The requirement to add a condensate reduces the profit margin per barrel of oil produced. Another alternative is to treat and upgrade the crude oil before injecting it into pipelines. Current treatment and upgrading techniques have been shown to be only economically viable in large plant capacities. Furthermore, these technologies are based on producing a variety of products. One of the advantages of this invention is providing a method of minimizing and/or eliminating price deductions related to produced crude oil quality and focuses on producing a single product stream that can be transported via the pipeline in small and large plant capacities.
Upgrading and treatment technologies, such as described in U.S. Pat. Nos. 4,294,686 and 5,069,775 and Canadian Patent 1,191,471 can be classified as either: (i) carbon rejection processes, (ii) non-carbon rejection processes, or (iii) combinations of either processes. Carbon rejection processes are based on removing a portion of the crude oil as a solid or semi-solid substance called coke. Coke production is commonly accompanied with gases being produced from severe cracking reactions. Usually the impurities remain in the coke. Poor process economics are typical for carbon rejection processes because liquid yields are generally between 65% and 80%. Non-carbon rejection processes are commonly known as visbreaking (viscosity breaking—an operation to reduce), reforming, alkylation, polymerization, and hydrogen-refining methods. These non-carbon rejection processes result in liquid yields between 90% to 105%.
This invention is based on the following design criteria:                1. Small and large plant capacities that are of modular construction, which can be deployed at field production batteries to produce a single liquid product stream, and        2. A process designed to produce highly favorable process economics by (i) maximizing product yields, (ii) minimizing product viscosity, (iii) minimizing density, (iv) maximizing the removal of contaminants, (v) minimizing capital equipment costs, and (vi) minimizing processing costs.Heavy crude oils are generally hydrogen deficient and are best amendable for treatment with hydrogenation processes. A hydrogenation process best satisfies the design criteria. Hydrogenation processes for refining are classified as destructive or nondestructive techniques. Crude oil exists as homologous fractions that have boiling point ranges between 36° C. (97° F.) to 553° C. (1027° F.). The denser and larger boiling point fractions are composed of long chain hydrocarbons. To minimize density and viscosity, these long chain hydrocarbon need to be broken into fragments. The fragmentation is accomplished by cracking reactions. Generally, cracking reactions occur at temperatures above 343° C. (650° F.). Destructive hydrogenation is achieved by cracking the liquid hydrocarbon molecular bonds and accompanied by hydrogen saturation of the fragments to create stable lower boiling point products, such as described in Canadian patent 1,191,471. This technique employs moderate processing conditions and high-pressure hydrogen that minimizes polymerization and condensation which minimizes coking. Destructive hydrogenation processes generally are operated at pressures from 1,000 psi to 3,000 psi and at a temperature in the order of 538° C. (1000° F.). Non-destructive hydrogenation is generally used for the purpose of improving product quality without appreciable alterations of the boiling point range or density. Milder processing conditions are employed for the removal of undesirable products. These undesirable products include sulfur, nitrogen, oxygen, olefins, and heavy metals.        
Other examples of upgrading and viscosity reduction processes involving the use of hydrogen at high temperatures and pressures and always under catalytic conditions are described in German application 1,933,857; Canadian patent 1,272,461; U.S. Pat. No. 3,598,722, and WO 97/29841.